| 摘要 |
PROBLEM TO BE SOLVED: To recover a potential energy of a lifted/lowered working part to an accumulator and to reuse the energy while reducing a loss. SOLUTION: This hydraulic control system is provided with an unloading valve 41 for returning pressure oil of a head side oil chamber 8a of a first boom cylinder 8 out of first and second boom cylinders 8, 9 for lifting/lowering the working part 4 to an oil tank. During lowering of the working part 4, the unloading valve 41 is opened, to hold the weight of the working part 4 by the pressure of a head side oil chamber 9a of the second boom cylinder 9. The hydraulic control system is further provided with an accumulator oil passage 45 for interconnecting the head side oil chambers 8a, 9a and an accumulator 44. Via the accumulator oil passage 45, oil discharged from the head side oil chamber 9a of the second boom cylinder 9 is accumulated in the accumulator 44 during the lowering of the working part 4, and accumulated oil of the accumulator 44 is supplied to the both head side oil chambers 8a, 9a during lifting of the working part 4. COPYRIGHT: (C)2010,JPO&INPIT |
